This invention relates generally to an improved solar heat collector panel and methods of manufacturing such panels.
Solar heat collectors are becoming widely used as sources of energy for heating swimming pools, building space and usable hot water. The collector, placed to receive maximum exposure to the sun, generally includes a flat absorber plate with a heat absorbing surface and ducts attached thereto for carrying fluid. The fluid is heated from the heat absorbing surface and then transferred to a heat storage reservoir. Liquid or air can be utilized as the heat transfer medium.
These main components of a solar heat collector are generally located inside an enclosure having a light transparent glazing spaced a distance from the black absorbing surface. The purpose of the cover is to prevent heated air from the vicinity of the absorber from escaping the collector and being lost to the atmosphere. It has been a constant goal in solar collector design to improve their efficiency; that is, to improve the proportion of incident sunlight energy that is converted into usable heat that may be transported to a location where it is desired.
Even with the use of a glazing in a solar collector, its collection efficiency (defined as a ratio of actually collected and primary incident energy) is generally significantly less than unity. This is due, in part, to losses between the heat transfer medium and the lower ambient temperature of the surroundings. Such losses are principally due to air convection in front of the heat absorber which carrier heat away from it to the atmosphere. In the case of solar heat collectors that have no transparent cover (unglazed), convection currents constantly replace the warm heated air adjacent the absorber with cooler ambient air which is then, in turn, heated by the absorber and lost. Where the collector is covered by a light transparent medium (glazed), the convection currents are still present in existing solar collectors and result in transferring heat from the absorber to the cooler glazing. The glazing then transmits this heat by direct conduction to the surrounding atmosphere. Such heat losses are a particular problem for solar domestic water heating, space heating and air conditioning where the temperature of the fluid transfer medium is maintained a great deal above the ambient temperature of the surroundings.
Therefore, it is a principal object of the present invention to provide a solar heat collector construction that results in a higher efficiency utilization of the solar energy incident upon it.
It is another object of the present invention to provide an improved technique for attaching a fluid heat transfer medium carrier to a heat absorber plate.